Stanley P. Owen and B. K. Bhuyan describe the isolation of the crystalline antibiotic 2H-Pyran-2-one, 6-(1,2-epoxypropyl)-5,6-dihydro-5-hydroxy acetate, which they refer to as U-13,933, in their article "Biological Properties of a New Antibiotic, U-13,933", Antimicrobial Agents and Chemotherapy-1965, copyright 1966, pp. 804-807.
A. D. Argoudelis and J. F. Zieseri described further structural specifications of the antibiotic U-13,933 in "The Structure of U-13,933, A New Antibiotic", Tetrahedron Letters No. 18, pp. 1969-1973, 1966.
U.S. Pat. No. 3,909,362 (Jiu et al.) discloses and claims a process for the production of the antimicrobial agents 5,6-dihydro-5-(S)-acetoxy-6(S)-(1',2'-trans-epoxypropyl)2H-pyran-2-one, 5,6-dihydro-5-(R)-acetoxy-6-(S)-(1',2'-trans-epoxypropyl)2H-pyran-2-one, and 5,6-dihydro-5(S)-acetoxy-6-(S)-(1',2'-trans-propenyl)2H-pyran-2-one comprising growing Aspergillus sp. NRRL 5769 or Aspergillus sp. NRRL 5770 in an aqueous nutrient medium containing sitosterol or sitostenone and isolating the compounds from the medium.
The three metabolites taught in the Jiu et al. patent, above, were further explained as showing antimicrobial activity against C. albicans, and against specific bacteria, fungi and a trichomonad by S. Mizuba et al. in "Three antimicrobial metabolites from Aspergillus caespitosus", Can. J. Microbiol., Vol. 21, 1975, pp. 1781-1787.
In their article "Total Synthesis of (+)-Asperlin", Tetrahedron:Assymetry Vol. 1, No. 3. pp. 137-140, 1990, Subban Ramesh and Richard W. Franck describe a stereochemically unambiguous synthesis of (+)-asperlin, a crystalline antibiotic from Aspergillus nidulans, from L-rhamnose and cite the configuration of the antibiotic as 4S, 5S, 6S, 7R.